Deconstructing Ethereum Fusaka Upgrade: The Evolution of Scaling Behind 12 EIPs

On June 20, at the 214th Ethereum Executive Core Developers Meeting (ACDE), core developers agreed to keep the final scope of the Fusaka upgrade basically unchanged, adding only one additional EIP (EIP 7939), covering 12 EIPs, which also marked that Fusaka officially entered the "substantial implementation" stage from "planning".

As the largest hard fork bundle upgrade since The Merge, the market generally expects that if Fusaka can be launched as planned by the end of 2025, it will bring another round of orders of magnitude improvement to the L2 data space, and L2 transaction fees may be further reduced in the next 1-2 years, thereby consolidating Ethereum's position in front of its competitors.

The continuous expansion logic of the Ethereum roadmap

As we all know, Ethereum's scalability problem was once the core bottleneck for the high cost of mainnet chain and the difficulty of popularizing DApp.

According to the data publicly shared by Vitalik in April this year, the current throughput of Ethereum L1 is 15 transactions per second, and the Gas limit has recently been increased to 36 million, which has increased by about 6 times in the past 10 years.

At the same time, more significant changes have occurred in Ethereum L2. The current L2 throughput has reached about 250 TPS, and it has made significant progress in scalability. This capability is not only limited to book data. Many users have also clearly felt the reduction in fees and acceleration of on-chain operations:

Over the past year, whether it is Arbitrum, Optimism or Base, L2 transfer fees have generally dropped to the US$0.01 range or even lower, a decrease of one or even multiple orders of magnitude compared to the previous level. The daily Gas cost of the Ethereum mainnet has also become significantly more friendly (of course, the impact of market conditions and on-chain activity is not ruled out).

This transformation is not accidental, but the result of Ethereum's strict construction according to the diagram and continuous iteration to advance the roadmap. We can briefly review the key upgrades of the Ethereum network in recent years:

• In 2022, Ethereum successfully switched to the PoS mechanism through The Merge upgrade, greatly reducing energy consumption and freeing up execution layer bandwidth for subsequent upgrades;

• In 2024, the Dencun upgrade was successfully activated, introducing the Blob data mechanism, for L2 It provides low-cost, temporary storage space, which drastically reduces the cost of Rollup and opens the channel for scalability;

• The recent Pectra upgrade was successfully launched on May 7, which greatly optimized the validator operation process and enhanced the flexibility of participating in the PoS system;

The next Fusaka upgrade is a key step in continuing the above process.

According to the latest statement by Tomasz Kajetan Stańczak, co-executive director of the Ethereum Foundation, Fusaka will be launched on the mainnet in the third or fourth quarter of 2025 (time to be finalized), and plans to implement multiple core EIPs including PeerDAS data availability sampling, further promoting Ethereum from performance bottlenecks to mainstream applicability.

It can be said thatfrom The Merge → Dencun → Pectra → Fusaka, Ethereum is moving in an orderly manner towards its long-term blueprint,that is, to build a global network that is secure, scalable, decentralized and sustainable.

Fusaka Upgrade Panorama

From the 12 core EIPs included in this upgrade, it basically covers multiple technical dimensions such as data availability, node lightweight, EVM optimization, and execution layer and data layer coordination mechanism.

Among them, the most popular proposal for this Fusaka upgrade is EIP‑7594 (PeerDAS), which introduces the "Data Availability Sampling (DAS)" mechanism, allowing validators in the network to complete verification by downloading only part of the Blob data without having to store all the data in full.

This greatly reduces the burden on the network, improves verification efficiency, and paves the way for L2's large-scale transaction processing capabilities. The concept of "Blob" here dates back to EIP-4844 introduced in the Dencun upgrade in 2024.

As the most important milestone of Ethereum in 2024, the Dencun upgraded EIP-4844 enabled transactions carrying Blobs for the first time, allowing L2s to choose not to use the traditional calldata storage mechanism, thereby greatly improving the Gas fees required for transactions and transfers on L2.

So what is a transaction carrying Blobs? In short, a large amount of transaction data is embedded in Blob, which can significantly reduce the storage and processing burden of the Ethereum mainnet, and is not included in the Ethereum mainnet state, directly solving the L1 cost problem related to data availability, and ensuring that the L2 platform can provide cheaper and faster transactions without affecting the security and decentralization based on Ethereum.

The Blob expansion here is also based on Pectra - the Pectra upgrade in May has increased the Blob capacity from 3 to 6. It is worth mentioning that Vitalik has publicly stated that ideally, Fusaka will expand the Blob capacity to 72/block (first phased increase to 12~24), and if DAS is fully implemented in the future, the theoretical maximum capacity can reach 512 Blobs/block.

Once implemented, L2's processing power (TPS) is expected to jump to tens of thousands, which will greatly improve the availability and cost structure of high-frequency interaction scenarios such as DApp, DeFi, social networks, and games on the chain. This is also one of the core directions of the "L2 Security and Finalization Roadmap" previously proposed by Vitalik.

At the same time, Fusaka also plans to lightweight the state and node structure by introducing the Verkle tree, which can not only significantly compress the state proof volume, making light clients and stateless verification possible, but also help promote the decentralization of Ethereum and the popularization of mobile terminals.

In addition, Fusaka also pays attention to the flexibility and performance bottlenecks of the virtual machine layer (EVM), including the following proposals:

• EVM and contract optimization rely on EIP‑7939 (CLZ opcode): efficient implementation of bit operations and accelerated encryption operations;

• EIP‑7951 (secp256r1 alternative support): Improve compatibility with Web2 and enterprise architecture;

• EIP‑7907: Expand the upper limit of contract size, support the deployment of more complex logic, and improve developer flexibility;

In order to ensure that the expansion does not affect the stability of the network, Fusaka also introduced EIP‑7934 to set a block size limit to ensure that the block will not be too heavy due to the Blob expansion, and adjusted the Blob usage fee through EIP-7892 / EIP-7918 to prevent the abuse of resources and dynamically match the supply and demand fluctuations.

The watershed between Ethereum expansion and experience?

From the overall perspective, we will find that Fusaka is not only a technical upgrade, but also has the potential to lay a bridge from "scalability to availability" at multiple key levels.

For example, for Rollup developers, it means lower data writing costs and more flexible interaction space; for wallets and infrastructure providers, it means supporting more complex interactions and heavier-loaded node environments; for end users, it means experiencing on-chain operations with lower costs and faster responses; for enterprises and compliant users, EVM expansion and simplified state proofs will also make on-chain interactions easier to access regulatory systems and large-scale deployment.

However, we still have to remain cautiously optimistic.

Overall, Fusaka is not limited to the enhancement of on-chain expansion capabilities, but also represents a key step in Ethereum's transition to mainstream commercial applications and ordinary users, and is expected to provide a technical foundation for the next stage of Rollup ecology, enterprise-level Dapp, and on-chain user experience.

The real watershed for Ethereum to move towards large-scale mainstream applications may be approaching.